Plant water limitation and its impact on the oviposition preferences of the monarch butterfly, Danaus plexippus (Lepidoptera: Nymphalidae)

Intensifying drought conditions across the western United States due to
global climate change are altering plant-insect interactions. Specialist
herbivores must find their host plants within a matrix of nonhosts, and
thus often rely upon specific plant secondary chemistry for host location
and oviposition cues. Climate-induced alterations to plant chemistry could
thus affect female selection of larval food-plants. Here, we investigated
whether host-plant water limitation influenced oviposition preference in a
threatened invertebrate: the monarch butterfly (Danaus plexippus). We
found that females deposited more eggs on reduced-water than on
well-watered narrowleaf milkweed plants (Asclepias fascicularis), but we
could not attribute this change to any specific change in plant chemistry.
Specialist herbivores, such as the monarch butterfly, which are tightly
linked to specific plant cues, may experience a shift in preferences under
global-change conditions. Understanding oviposition preferences will be
important to directing ongoing habitat restoration activities for this
declining insect.